1. Field of the Invention
The invention relates to the field of lighting devices for a motor vehicle. The invention concerns in particular such devices using electronic components sensitive to electrostatic discharges, such as light-emitting diodes, for example.
2. Description of the Related Art
In the field of lighting devices for motor vehicles, the use of light sources such as light-emitting diodes (LED), organic light-emitting diodes (OLED) or laser diodes is increasingly specified. The placement of these lighting means along precise contours in actual fact makes it possible to create interesting and individual optical signatures. However, these are sensitive electronic components, notably sensitive to electrostatic discharges. During the service life of a motor vehicle, such components may be exposed to electrostatic discharges inside the headlight of which they form part. For example, because of friction of the external air on the outer lenses of a headlight, portions of the latter may come to carry static charges. If the light sources are subjected to discharges coming from these portions, there is a high risk of premature deterioration or even premature destruction of the electronic components.
In order to protect light sources, it is known to provide protection electronic circuits in the lighting device. For example, an electrical capacitor may be connected in parallel with an LED, the capacitor being able to absorb any surge. However, the cost of such a solution increases in proportion to the number of LEDs used. Moreover, such protection circuits occupy a large portion of the respective printed circuit boards, and the amount of room inside the device is limited.
The patent document US 2002/0151200 A1 describes a circuit element for protecting an electronic device from surges that occur within the electronic circuit including a sensitive component. Such a system can be useful only if the surge can occur only at a predefined location of the circuit to be protected. Means adapted to redirect the surge to ground on the upstream side of the sensitive component may then be incorporated in the circuit to the protected. Such a solution is not applicable to cases as described, however, in which an electrostatic discharge may occur at random to an electronic circuit including one or more sensitive components. As the discharge can occur in different portions of the circuit to be protected, this known solution is not able to solve the problem described.